The offer comes in a disturbing new video.

The Nigerian Islamist group Boko Haram released a video on Sunday blaming Nigerian airstrikes for killing many of the girls it abducted more than two years ago and offering to exchange the survivors for its imprisoned fighters.

A masked militant appears in the video with a group of about 50 girls behind him, purportedly some of the more than 200 schoolgirls the group abducted from Chibok, in northeast Nigeria. The bodies of those allegedly killed or wounded in government airstrikes also appear in the video.

“We are being extremely careful because the situation has been compounded by the split in the leadership of Boko Haram,” Nigerian Information Minister Alhaji Mohammed continued. “We are also being guided by the need to ensure the safety of the girls.”

The New York Timesreported that a spokesman for the Bring Back Our Girls campaign said the video seems legitimate, adding that some family members recognized several of the girls.

At least one kidnapped schoolgirl was found earlier this year. Nigeria celebrated when a civilian militia found her in the forest with a baby, confirming what many feared – that the girls became sex slaves and married off to Boko Haram fighters.

Meanwhile, the BBC reported that the Nigerian army is searching for journalist Ahmad Salkida, who has written about the internal workings of Boko Haram. Salkida, believed to be in Dubai, wrote about the video before its release.